In the sit com, Cristela, two trainees in a law firm are trying to earn a promotion by appealing foe their boss who likes sports so much. One of them, Cristela manages to gain her boss support by talking with him about sports. on the other hand, Josh who is more interested in theatre and musicals is afraid that he will lose his chance for the promotion. Finally, Cristela decides to help him by asking him to put a blue tooth in his ear and repeat everything she says when he goes to meet their boss, which reminds him of Cyrano de Bergerac. Then he asks her "Well, it's no "A Chorus Line," am I right?" and she answers "Maybe I should just go in there and pretend to be you." I understand that "A chorus Line" is another musical but what is its significance here?

 

People who write sitcom scripts try to have the characters say things in clever and funny ways, instead of simple and clear ways. Sometimes the result is a joke that does not make sense to anyone, so it isn't funny.

According to your explanation, his comment ("Well, it's...) refers to the game they are about to play, using a blue tooth earpiece. Yes?

It reminds him of a famous scene in a play (Cyrano de Bergerac). He compares it with a very famous, very popular hit Broadway show. He says it is not as <something> as that Broadway show. It cannot compete for <somethingness> with a full Broadway show.

I don't think there is any significance to the show he picked to name, other than it being very successful.

 

I agree with dojibear. A Chorus Line is one of the most famous and longest-running Broadway musicals of all time. I don't think there's any more to it than that.

 

There is some dialogue missing in the part OP paraphrased. After Josh compares the bluetooth-in-ear situation to Cyrano, he then states the "fun fact" that the author of the play (Edmund Rostand) also wrote the play later adapted as the Off-Broadway musical The Fantasticks. Cristela responds with a quip that that might be a fact, but it's not all that "fun." Josh misunderstands her remark as critiquing The Fantasticks and replies, "Well, it's not A Chorus Line, am I right?"

The main purpose of the lines are to show Josh is such a theater nerd that he is unable to grasp that Cristela is trying to tell him that he's being one; he assumes she is responding to his musical trivia in kind.

There's also an in-joke for musical theater enthusiasts: A Chorus Line's original Broadway run was 1975-1990, making it a record holder until displaced by Cats, but The Fantasticks opened in 1960 and ran for 42 years!